Double Patch Regular Polyhedron   The rectangle 94*68 mm, the sides of the cutting plane 28 and 16 mm rack Diameter 6 mm.
each patch has an input impedance of 100 Ohms, between 0.5 *Lambda of the connecting line. Obtained by parallel connection of 50 Ohms.
And cool chart SWR
the broadband is a patch in the form of an pseudo- ellipse with eccentricity 0.8, 2 Patches of narrow-band, but with the increase of the gap band of operating frequencies increases at 0.1 Lambda reaches 10/11 %. When band gaps, increases the ability of multi-mode excitation. With the increase of the gap increases and the value of the input impedance.
Based on this information, can built a patch with a gap from the reflector is 15 mm.
The line length is 0.5 L, so its width is not critical. In this project its width is about 2 mm d = 1 mm
The gap( between the surfaces) 15 mm width  to reflector Conn. line 13 mm.
the distance between the two coherent emitters choose, usually based on two criteria. Or the maximum gain, then it's 1 lambda or a little more. Or at a minimum side lobes, then it is less than lambda, about 0.7/0.8.